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From: Nick Kossifidis <mick@ics.forth.gr>
To: Matteo Croce <mcroce@linux.microsoft.com>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Atish Patra <atish.patra@wdc.com>,
	Emil Renner Berthing <kernel@esmil.dk>,
	Akira Tsukamoto <akira.tsukamoto@gmail.com>,
	Drew Fustini <drew@beagleboard.org>,
	Bin Meng <bmeng.cn@gmail.com>,
	David Laight <David.Laight@aculab.com>,
	Guo Ren <guoren@kernel.org>
Subject: Re: [PATCH v3 0/3] riscv: optimized mem* functions
Date: Tue, 22 Jun 2021 04:09:14 +0300	[thread overview]
Message-ID: <e968312557f147af1e5efb341eeef0ad@mailhost.ics.forth.gr> (raw)
In-Reply-To: <20210617152754.17960-1-mcroce@linux.microsoft.com>

Hello Matteo,

Στις 2021-06-17 18:27, Matteo Croce έγραψε:
> From: Matteo Croce <mcroce@microsoft.com>
> 
> Replace the assembly mem{cpy,move,set} with C equivalent.
> 
> Try to access RAM with the largest bit width possible, but without
> doing unaligned accesses.
> 
> Tested on a BeagleV Starlight with a SiFive U74 core, where the
> improvement is noticeable.
> 

There are already generic C implementations for memcpy/memmove/memset at 
https://elixir.bootlin.com/linux/v5.13-rc7/source/lib/string.c#L871 but 
are doing one byte at a time, I suggest you update them to do 
word-by-word copy instead of introducing yet another memcpy/memmove C 
implementation on arch/riscv/.




WARNING: multiple messages have this Message-ID (diff)
From: Nick Kossifidis <mick@ics.forth.gr>
To: Matteo Croce <mcroce@linux.microsoft.com>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-arch@vger.kernel.org,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Atish Patra <atish.patra@wdc.com>,
	Emil Renner Berthing <kernel@esmil.dk>,
	Akira Tsukamoto <akira.tsukamoto@gmail.com>,
	Drew Fustini <drew@beagleboard.org>,
	Bin Meng <bmeng.cn@gmail.com>,
	David Laight <David.Laight@aculab.com>,
	Guo Ren <guoren@kernel.org>
Subject: Re: [PATCH v3 0/3] riscv: optimized mem* functions
Date: Tue, 22 Jun 2021 04:09:14 +0300	[thread overview]
Message-ID: <e968312557f147af1e5efb341eeef0ad@mailhost.ics.forth.gr> (raw)
In-Reply-To: <20210617152754.17960-1-mcroce@linux.microsoft.com>

Hello Matteo,

Στις 2021-06-17 18:27, Matteo Croce έγραψε:
> From: Matteo Croce <mcroce@microsoft.com>
> 
> Replace the assembly mem{cpy,move,set} with C equivalent.
> 
> Try to access RAM with the largest bit width possible, but without
> doing unaligned accesses.
> 
> Tested on a BeagleV Starlight with a SiFive U74 core, where the
> improvement is noticeable.
> 

There are already generic C implementations for memcpy/memmove/memset at 
https://elixir.bootlin.com/linux/v5.13-rc7/source/lib/string.c#L871 but 
are doing one byte at a time, I suggest you update them to do 
word-by-word copy instead of introducing yet another memcpy/memmove C 
implementation on arch/riscv/.




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  parent reply	other threads:[~2021-06-22  1:09 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-17 15:27 [PATCH v3 0/3] riscv: optimized mem* functions Matteo Croce
2021-06-17 15:27 ` Matteo Croce
2021-06-17 15:27 ` [PATCH v3 1/3] riscv: optimized memcpy Matteo Croce
2021-06-17 15:27   ` Matteo Croce
2021-06-18 14:06   ` kernel test robot
2021-06-18 14:06     ` kernel test robot
2021-06-18 14:06     ` kernel test robot
2021-06-21 14:26   ` Christoph Hellwig
2021-06-21 14:26     ` Christoph Hellwig
2021-06-22  8:19     ` David Laight
2021-06-22  8:19       ` David Laight
2021-06-22 22:53       ` Matteo Croce
2021-06-22 22:53         ` Matteo Croce
2021-06-22 22:00     ` Matteo Croce
2021-06-22 22:00       ` Matteo Croce
2021-06-22  0:14   ` Nick Kossifidis
2021-06-22  0:14     ` Nick Kossifidis
2021-06-22 23:35     ` Matteo Croce
2021-06-22 23:35       ` Matteo Croce
2021-06-23  9:48       ` Nick Kossifidis
2021-06-23  9:48         ` Nick Kossifidis
2021-06-17 15:27 ` [PATCH v3 2/3] riscv: optimized memmove Matteo Croce
2021-06-17 15:27   ` Matteo Croce
2021-06-21 14:28   ` Christoph Hellwig
2021-06-21 14:28     ` Christoph Hellwig
2021-06-22  0:46   ` Nick Kossifidis
2021-06-22  0:46     ` Nick Kossifidis
2021-06-30  4:40   ` kernel test robot
2021-06-30  4:40     ` kernel test robot
2021-06-30  4:40     ` kernel test robot
2021-06-17 15:27 ` [PATCH v3 3/3] riscv: optimized memset Matteo Croce
2021-06-17 15:27   ` Matteo Croce
2021-06-21 14:32   ` Christoph Hellwig
2021-06-21 14:32     ` Christoph Hellwig
2021-06-22  1:07   ` Nick Kossifidis
2021-06-22  1:07     ` Nick Kossifidis
2021-06-22  8:38     ` David Laight
2021-06-22  8:38       ` David Laight
2021-06-23  1:14       ` Matteo Croce
2021-06-23  1:14         ` Matteo Croce
2021-06-23  9:05         ` David Laight
2021-06-23  9:05           ` David Laight
2021-06-23  0:08     ` Matteo Croce
2021-06-23  0:08       ` Matteo Croce
2021-06-22  1:09 ` Nick Kossifidis [this message]
2021-06-22  1:09   ` [PATCH v3 0/3] riscv: optimized mem* functions Nick Kossifidis
2021-06-22  2:39   ` Guo Ren
2021-06-22  2:39     ` Guo Ren

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